Mineral Composition of Cereal and Cereal-Free Dry Dog Foods versus Nutritional Guidelines

Abstract

The aims of the present work are to estimate the nutritional value and to evaluate and compare the levels of macroelements (Ca, P, K, Na, Mg), microelements (Fe, Zn, Mn, Cu), heavy metals (Co, Cd, Pb, Mo, Cr, Ni), and their ratios in extruded complete foods for adult dogs, their compatibility with nutritional guidelines, as well as food profile similarity. Basic composition was determined according to Association of Official Analytical Chemists (AOAC). Analyses for elements were performed using an atomic absorption spectrometer. All the evaluated dry dog foods met the minimum recommended levels for protein and fat. Eighteen tested dog foods (60%) did not meet at least one recommendation of nutritional guidelines. Four dog foods exceeded the legal limit of Fe and five foods exceeded the legal limit of Zn; in one of them, Zn level was almost twice higher. Dog foods with insect protein exceeded the legal limit for Mn content. Eight dog foods had an inappropriate Ca:P ratio. Heavy metals were below detection limit in all analyzed dog foods. The results seem to show the need for regular feed analyses of the elemental composition in raw materials before introducing supplementation and for the monitoring of the mineral composition of finished pet food.

Nutritional Evaluation and Risk Assessment of the Exposure to Essential and Toxic Elements in Dogs and Cats through the Consumption of Pelleted Dry Food: How Important Is the Quality of the Feed?

“…To our knowledge, this is the first time that many of these potentially toxic elements have been analyzed in commercial pet food [14,22]. A previous publication has considered these elements but in home-prepared diets for adult pets [23].…”

“…Not only are there no significant differences in the content of essential elements between premium and low-cost brands but, on some occasions, the content of these elements is not adjusted to the nutritional requirements of pets. Recently, a published study has drawn attention to the need for routine analysis of the essential composition of raw materials before introducing any type of supplementation [14]. In this and other studies, it is common to see that the amounts of some essential elements, selenium and manganese among them, are usually over-supplemented, sometimes exceeding the established legal limits [36,37].…”

“…However, this assumption is not supported by published scientific data that have shown that there are no differences in mycotoxin levels depending on whether the feed is "of quality" or not [10]. In some cases, the mineral composition of dry dog foods does not conform to the requirements given by nutritional guidelines, exceeding the legal limit for iron or zinc in a large number of samples [14].…”

Evaluation of nutritional value and microbiological safety in commercial dog food

“…Cerealfree foods also had a higher average content of EE than cereal foods, which may be due to, among others, the main plant ingredients used. Most of the tested cereal foods contained rice as the main plant component and most cereal-free foods contained peas, which are marked by higher amounts of fat than rice (Tulbek et al 2017;Sandri et al 2019;Ismagilov et al 2020).…”

“…There is a substantial interest in the topic of grain-free trend in pet food sector (Meineri et al 2020 ). The presence or absence of cereals may affect the nutritional value of the finished product (Pezzali and Aldrich 2019 ; Kazimierska et al 2020 ), thus it is worth paying attention to these ingredients when choosing a dog food. However, it seems that “grain-free” is a marketing term rather than scientific definition.…”